Not to be overly with the semantics, but it seems like there’s a very simple solution to all this.
Sexual situations should have associated terminology that is reserved for sexual situations.
Bodily responses should also have their own, separate language.
That would solve this totally made up problem that language creates.
Rape victims would not have to associate their physiological response with sex.
Nursing moms would not have to explain their physiological reactions to their nursing babies using sexual language.
And look—as an incest survivor, I think it’s actually extremely important to recognize that sex is not the same as what someone does to your body.